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US 6,606,420 B1Granted
Method and apparatus for digital image darkness control in saturated image structures
AssigneeXerox Corporation
InventorsRobert P. Loce, Clara Cuciurean-Zapan, Yeqing Zhang
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Abstract
A method and apparatus for the control of darkness/lightness in a digital image rendered by a printing system. An original image containing antialiased edges is initially thresholded and filtered to determine an edge map. With knowledge of the edge via the edge map, darkness adjustment is applies to the digital image. Gray-edge compaction is applied thereafter to adjust the position of the edge.
Claims8
A method of altering a darkness level of a digital image, comprising the steps of:
- receiving a set of image signals including gray edges;
- isolating, within said set, said gray edges and generating an edge map therefrom;
- using the edge map, varying gray by a selected amount at the edge of said image, so as to change the output level of at least one pixel along the border region;
- and
- compacting diffuse gray values at edges of said image, to minimize gray pixels at said edges.
2 more elements
A digital darkness control system, for adjusting darkness/lightness of antialiased edges, including;
- an image input, receiving images including gray edges;
- an antialiased edge detector identifying gray edges in said received images;
- darkness/lightness adjustment, responsive to user control, logically adjusting darkness and lightness by combining or removing gray at said edges
- gray edge compaction, minimizing diffuse gray edges and maintaining gray values at said edge;
- and
- an image output, outputing said darkness/lightness adjusted edges.
3 more elements
Dependencies are inferred from the claim text.